<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .pink{
            background-color: pink;
        }
    </style>
</head>
<body>
    <button class="pink">按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <button>按钮4</button>
    <script>
        // 获取页面中的按钮
        let btns=document.querySelectorAll('button')
        console.log(btns)
        // 遍历按钮
        for(let i=0;i<btns.length;i++){
            btns[i].addEventListener('click',function(){
                document.querySelector('.pink').className=''
                this.className='pink'
            })
        }
    </script>
</body>
</html>